Isenate race, probably the most watched individual contest of the midterms, Nick Allen writes in El Paso, Texas,
El Paso, a sleepy city on the Mexican border, is the home town of Beto O'Rourke, the Democrat candidate.
"Betomania" erupted on Monday night as Mr. O'Rourke was his final election candidate.
The skateboard loving, former punk rocker was introduced by a mariachi band and then bound on stage, high-fiving supporters.
As he spoke Mr O'Rourke was drowned out by cheers. Some in the packed auditorium were weeping as they waved "Viva Beto" signs.
Mr. O'Rourke said: "We are days away from achieving something incredible in Texas." "If we keep this up tomorrow we will be celebrating the victory of our lifetimes."
He called it an election that "wants to define the future not just of Texas, but this country, not just this generation, but every generation that follows". Shouted with a thumbs up: "Let's win this!"
Outside the rally Mr O'Rourke told journalists he would campaign until the last minute.
Putting his arm around his wife Amy, he said: "We're giving it all we've got, as we have done from the very first day."